Advice? Closed Zoas & High pH

Why were you dosing calcium and alkalinity? What was your alkalinity before you started dosing? A good range is 9 to 12 but it could even be lower. If you need to dose, you should test before and while dosing to make sure the levels are ok. pH of 8.2 is normal seawater level so I would leave it there. If it goes down the next time you do a water change, that is fine. 7.8 to 8.3 is fine for pH. If you make changes, like the bringing down of your pH, it is best to do them slowly. The quick change can kill things. I'd leave everything the way it is. Don't dose unless you need to and test if you dose. It might take a while for them to open again.

 

I am no expert yet, but I think you need to determine if dosing is even needed. If your water changes are regular and frequent enough and you just have a few corals, your Ca and Alk should stay somewhat level. That will change if you keep adding to your tank.

When I decided to think about dosing 2 part, I started testing my Ca and Alk nearly everyday for a week to determine how much I was using. Then I calculated how long to dose based on what it would take to replenish what was used up. I then kept testing for the next week and tweaked the quantity of Ca and Alk until it was staying where I wanted it.

I still have to keep checking often for peace-of-mind, since the salt I am using is not exactly inline with the parameters I want my tank at. I could probably fix this by switching salts, but I don't want to throw out 2 full buckets.

 

Zoas wont use calc or alk. They however will consume iodine. If you add SPS or LPS then those will use calc, alk, and mag. If you only have a few of those corals a normal water change will be enough for them.

If you think you need to dose two part, you need to test your levels every day for a week until you can hit the perfect amount to dose each day. The levels you posted are where you want to be at. With what you have listed for corals a simple water change will be enough to sustain your tank until you stock it with more stoney corals.

 

With a DKH of 10 and a low alk demand I wouldn't advise dosing. I'm actually surprised it wasn't higher if it drove your pH to 8.8 (did you test shortly after dosing?). Ca is also pretty high but not threatening at that level (I believe Ca precipitation occurs somewhere around 500 ppm). A common word of wisdom you may have seen already is "don't bother chasing pH" and I would certainly agree. It's a good number to monitor as it can be a sign of another issue if you notice it drift (CO2/O2 or alk would be follow up items to check). So you can think of low pH as a symptom that you don't want to address pH in a direct fashion. A lot of people running calcium reactors end up in the 7.8-8.0 range without any issues.

Since you don't have any SPS in there you're not likely going to have a huge demand for alk/ca. Coralline algae growth will take up some if you have it going. Try this... After your next WC check your ca/alk. Wait around 1 week and retest.. this will at least give you a baseline for your weekly alk/ca demands. If you actually have a significant drop then you can start the iterative process of determining the weekly dosing required (more challenging than you may think). If your salt mix is one which is elevated in alk/ca already you will likely be able to get away without dosing altogether (red sea pro for example).

 

I can't imagine you're going to need to dose Iodine any time soon but if you do end up going that route be very careful. Most inverts are extremely sensitive to elevated iodine levels (especially shrimp as it plays with their molting). If you look at most of the test kits out there you'll see they only show you levels like 0.0, 0.3, 0.6, and >0.6. The challenge is that 0.6 is the ideal NSW level and above 0.6 suddenly gets dangerous. So this is a hard one to dose with any kind of precision.

I dosed iodine lightly for SPS coloration and was able to notice a difference in certain colors even though I was always testing at 0.0 even after dosing. The top chemist of our hobby (Randy Holmes-Farley) doesn't recommend dosing iodine at all.

Magnesium is a good kit to have on hand. If you notice you're having a hard time keeping Ca/alk in line Mg can sometimes be the culprit. However, I don't imagine you're going to need to dose Mg for a while yet.

This is a great article even though it's over a decade old now (still every bit as valid)..
http://reefkeeping.com/issues/2004-05/rhf/index.php

 

I agree. Don't dose anything unless you can test for it.
Choose the levels you want to maintain and keep them stable.
If you do dose, test everyday until you get your dosage amount and keep testing to make sure it's stable.
Dosing too much alkalinity will pissing everything off from the dramatic change. If you need to make corrections. Only go .5 dhk per day. And if you can spread the doses out. Like some in the morning and some later in the day.
I have a softie tank that all I have to do is a water change every week and my alkalinity stays at 8.0. I haven't dosed that tank yet and it's been setup since spring.

I also have an sps tank and I dose 120ml of alkalinity and 120ml calcium and 80ml magnesium per day along with 3 gallons per day automated water changes. The doses a spread out over the 24 hours and each part is dosed 10 minutes apart so they don't precipitate out.
I doubt you will need to dose anytime soon but if you do we can help you out with amounts or any other details you need.